全文获取类型
收费全文 | 728篇 |
免费 | 43篇 |
专业分类
耳鼻咽喉 | 11篇 |
儿科学 | 85篇 |
妇产科学 | 15篇 |
基础医学 | 101篇 |
口腔科学 | 14篇 |
临床医学 | 56篇 |
内科学 | 137篇 |
皮肤病学 | 4篇 |
神经病学 | 41篇 |
特种医学 | 7篇 |
外国民族医学 | 1篇 |
外科学 | 77篇 |
综合类 | 12篇 |
预防医学 | 61篇 |
眼科学 | 18篇 |
药学 | 86篇 |
1篇 | |
中国医学 | 3篇 |
肿瘤学 | 41篇 |
出版年
2024年 | 10篇 |
2023年 | 15篇 |
2022年 | 22篇 |
2021年 | 47篇 |
2020年 | 20篇 |
2019年 | 25篇 |
2018年 | 33篇 |
2017年 | 24篇 |
2016年 | 33篇 |
2015年 | 33篇 |
2014年 | 42篇 |
2013年 | 40篇 |
2012年 | 69篇 |
2011年 | 57篇 |
2010年 | 38篇 |
2009年 | 23篇 |
2008年 | 33篇 |
2007年 | 44篇 |
2006年 | 20篇 |
2005年 | 21篇 |
2004年 | 27篇 |
2003年 | 21篇 |
2002年 | 18篇 |
2001年 | 6篇 |
2000年 | 1篇 |
1999年 | 1篇 |
1998年 | 4篇 |
1997年 | 1篇 |
1996年 | 4篇 |
1995年 | 4篇 |
1994年 | 2篇 |
1993年 | 1篇 |
1992年 | 1篇 |
1991年 | 2篇 |
1990年 | 1篇 |
1989年 | 2篇 |
1987年 | 1篇 |
1986年 | 1篇 |
1985年 | 1篇 |
1983年 | 1篇 |
1982年 | 1篇 |
1981年 | 1篇 |
1980年 | 6篇 |
1979年 | 3篇 |
1978年 | 2篇 |
1977年 | 1篇 |
1965年 | 1篇 |
1963年 | 2篇 |
1960年 | 3篇 |
1959年 | 2篇 |
排序方式: 共有771条查询结果,搜索用时 0 毫秒
741.
742.
Alan R. Erickson Vishnu Reddy Scott A. Vogelgesang Sterling G. West 《Arthritis \u0026amp; Rheumatology》1995,38(8):1115-1119
Objective. To test the usefulness and cost savings resulting from application of the new American College of Rheumatology (ACR) guidelines for assessing the risk for the development of clinically significant liver disease in rheumatoid arthritis (RA) patients treated with methotrexate (MTX). Methods. One-hundred twelve MTX-treated RA patients were prospectively followed up for MTX hepatotoxicity and underwent liver biopsies according to modified guidelines of the Psoriatic Task Force (PTF). All biopsies were graded according to the Roenigk classification. The new ACR recommendations were then retrospectively applied to test their usefulness and cost-effectiveness in this cohort. Results. Based on the PTF guidelines, 66 patients underwent liver biopsies; a total of 110 liver biopsies were performed. Two patients had biopsy-related complications. Five patients were found to have Roenigk grade IIIB or IV histologic abnormalities. The total cost for this group was $111,380. Applying the new ACR criteria, only 15 patients would have undergone liver biopsies; there would have been a total of 18 biopsies, with no complications. Four of the 5 patients with Roenigk grade IIIB or IV liver abnormalities would have been identified. One patient with insulin-dependent diabetes mellitus (IDDM) who was found to have cirrhosis (Roenigk grade IV) on liver biopsy as a result of use of the PTF guidelines would have been missed with use of the ACR guidelines. The total cost for the group receiving biopsies based on the ACR guidelines would have been $16,956. Overall, the new ACR guidelines had 80% sensitivity and 82% specificity and resulted in a cost savings of $1,430 per patient. Conclusion. The new ACR guidelines on MTX monitoring and biopsy surveillance appear to be clinically useful and result in considerable cost savings. However, 1 IDDM patient with significant liver histologic abnormalities would have been missed. We suggest that IDDM be added to the ACR guidelines as a risk factor for MTX hepatotoxicity. 相似文献
743.
William J Mitchell Lindsey J Tepfer Nicole M Henninger Susan B Perlman Vishnu P Murty Chelsea Helion 《Social cognitive and affective neuroscience》2022,17(3):311
Developmental studies have identified differences in prefrontal and subcortical affective structures between children and adults, which correspond with observed cognitive and behavioral maturations from relatively simplistic emotional experiences and expressions to more nuanced, complex ones. However, developmental changes in the neural representation of emotions have not yet been well explored. It stands to reason that adults and children may demonstrate observable differences in the representation of affect within key neurological structures implicated in affective cognition. Forty-five participants (25 children and 20 adults) passively viewed positive, negative and neutral clips from popular films while undergoing functional magnetic resonance imaging. Using representational similarity analysis to measure variability in neural pattern similarity, we found developmental differences between children and adults in the amygdala, nucleus accumbens and ventromedial prefrontal cortex (vmPFC): children generated less pattern similarity within subcortical structures relative to the vmPFC—a phenomenon not replicated among their older counterparts. Furthermore, children generated valence-specific differences in representational patterns across regions; these valence-specific patterns were not found in adults. These results may suggest that affective representations grow increasingly dissimilar over the course of development as individuals mature from visceral affective responses to more evaluative analyses. 相似文献
744.
Varuna Jayachandran Vishnu Shankar Dhandapani Elango Muniappan Dongkyou Park Byungki Kim A. P. Arun P. R. Ayyappan 《Materials》2022,15(23)
In order to control diesel exhaust emission, CeO2-SnO2/Al2O3 (CTA) mixed oxides were prepared and coated on perforated stainless steel (SS) filter plates, and the catalytic activities were analyzed in this work. The CeO2-SnO2 (different compositions of Ce/Sn—2:8; 1:1; 8:2) composites and Al2O3 were prepared separately via a co-precipitation approach, and CeO2-SnO2/Al2O3 (CTA) mixed oxides were attained by mechanical mixing of 75 wt% CeO2-SnO2 composites with 25 wt% Al2O3. X-ray diffraction (XRD) and Raman spectroscopy were performed for all three CeO2-SnO2/Al2O3 (CTA) mixed oxides; the CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample confirmed the presence of cubic and tetragonal mixed faces, which enhances the redox nature (catalytic activities). Various characterizations such as high-resolution transmission electron microscopy (HRTEM), Brunauer–Emmett–Teller (BET) analysis, X-ray photoelectron spectroscopy (XPS), and a scanning electron microscope (SEM) were employed on CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample to investigate the structural, textural, compositional, and morphological properties. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample was coated on a perforated stainless steel (SS) filter plate via a simple, cost-effective, and novel method, and an exhaust emission test for various compression ratios (CR), injection pressure (IP), and load (L) was completed using an AVL Digas analyzer. The CeO2-SnO2/Al2O3 (Ce/Sn-1:1) sample, with a size of 10.22 nm and a high surface area of about 73 m2 g−1, exhibit appreciable catalytic properties. 相似文献
745.
Suresh R Naik Vishnu N ThakareSnehal R Patil 《Experimental and toxicologic pathology》2011,63(5):419-431
The present study investigates the protective effects of curcumin on experimentally induced inflammation, hepatotoxicity, and cardiotoxicity using various animal models with biochemical parameters like serum marker enzymes and antioxidants in target tissues. In addition, liver and cardiac histoarchitecture changes were also studied. Curcumin treatment inhibited carrageenin and albumin induced edema, cotton pellet granuloma formation. The increased relative weight of liver and heart in CCl4 induced liver injury and isoproterenol induced cardiac necrosis were also reduced by curcumin treatment. Elevated serum marker enzymes, aspartate aminotransferase (AST), alanine aminotransferase (ALT) and alkaline phosphatase (ALP) increased lipid peroxidation, decreased gluthione (GSH), glutathione peroxidase (GPx) and superoxide dismutase (SOD) in edematous, granulomatus, liver and heart tissues during inflammation, liver injury and cardiac necrosis, respectively. Curcumin treatment reversed all these above mentioned biochemical changes significantly in all animal models studied. Even histoarchitecture alterations observed in liver injury and cardiac necrosis observed were partially reversed (improved) by curcumin treatments. In in vitro experiments too curcumin inhibited iron catalyzed lipid peroxidation in liver homogenates, scavenged nitric oxide spontaneously generated from nitroprusside and inhibited heat induced hemolysis of rat erythrocytes. The present in vitro and in vivo experimental findings suggest the protective effect of curcumin on experimentally induced inflammation, hepatotoxicity, and cardiotoxicity in rats. 相似文献
746.
Govindasamy Rajakumar Abdul Abdul Rahuman Chidambaram Jayaseelan Thirunavukkarasu Santhoshkumar Sampath Marimuthu Chinnaperumal Kamaraj Asokan Bagavan Abdul Abduz Zahir Arivarasan Vishnu Kirthi Gandhi Elango Pooja Arora Rajan Karthikeyan Sivan Manikandan Sujin Jose 《Parasitology research》2014,113(2):469-479
Titanium dioxide nanoparticles (TiO2 NPs) are widely used in paints, printing ink, rubber, paper, cosmetics, sunscreens, car materials, cleaning air products, industrial photocatalytic processes, and decomposing organic matters in wastewater due to their unique physical, chemical, and biological properties. The present study was conducted to assess the antiparasitic efficacies of synthesized TiO2 NPs utilizing leaf aqueous extract of Solanum trilobatum against the adult head louse, Pediculus humanus capitis De Geer (Phthiraptera: Pediculidae); larvae of cattle tick Hyalomma anatolicum (a.) anatolicum Koch (Acari: Ixodidae), and fourth instar larvae of malaria vector Anopheles subpictus Grassi (Diptera: Culicidae). The green synthesized TiO2 NPs were analyzed by X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Scanning electron microscopy (SEM), Energy-dispersive X-ray spectroscopy analysis (EDX), and Atomic force microscopy (AFM). XRD analysis of synthesized TiO2 NPs revealed that the particles were in the form of nanocrystals as evidenced by the major peaks at 2θ values of 27.52°, 36.21°, and 54.43° identified as 110, 101, and 211 reflections, respectively. FTIR spectra exhibited a prominent peak at 3,466 cm?1 and showed OH stretching due to the alcoholic group, and the OH group may act as a capping agent. SEM images displayed NPs that were spherical, oval in shape, individual, and some in aggregates with an average size of 70 nm. Characterization of the synthesized TiO2 NPs using AFM offered a three-dimensional visualization and uneven surface morphology. The pediculocidal and acaricidal activities of synthesized TiO2 NPs showed the percent mortality of 31, 42, 63, 82, 100; 36, 44, 67, 89, and 100 at 2, 4, 6, 8, and 10 mg/L, respectively, against P. h. capitis and H. a. anatolicum. The average larval percent mortality of synthesized TiO2 NPs was 38, 47, 66, 79, and 100 at 1, 2, 3, 4, and 5 mg/L, respectively, against A. subpictus. The maximum activity was observed in the aqueous leaf extract of S. trilobatum, TiO(OH)2 solutions (bulk), and synthesized TiO2 NPs with LC50 values of 35.14, 25.85, and 4.34 mg/L; 47.15, 29.78, and 4.11 mg/L; and 28.80, 24.01, and 1.94 mg/L, and r 2 values of 0.982, 0.991, and 0.992; 0.947, 0.987, and 0.997; and 0.965, 0.998 and 0.985, respectively, against P. h. capitis, H. a. anatolicum, and A. subpictus. This study provides the first report on the pediculocidal, acaricidal, and larvicidal activity of synthesized TiO2 NPs. This is an ideal eco-friendly, novel, low-cost, and simple approach to satisfy the requirement of large-scale industrial production bearing the advantage for the control of P. h. capitis, H. a. anatolicum, and A. subpictus. 相似文献
747.
Chinnaperumal Kamaraj Abdul Abdul Rahuman Selvaraj Mohana Roopan Asokan Bagavan Gandhi Elango Abdul Abduz Zahir Govindasamy Rajakumar Chidambaram Jayaseelan Thirunavukkarasu Santhoshkumar Sampath Marimuthu Arivarasan Vishnu Kirthi 《Parasitology research》2014,113(5):1657-1672
Malaria is an overwhelming impact in the poorest countries in the world due to their prevalence, virulence and drug resistance ability. Currently, there is inadequate armoury of drugs for the treatment of malaria. This underscores the continuing need for the discovery and development of new effective and safe antimalarial drugs. To evaluate the in vitro and in vivo antimalarial activity of the leaf ethyl acetate extract of Murraya koenigii, bioassay-guided chromatographic fractionation was employed for the isolation and purification of antimalarial compounds. The in vitro antimalarial activity was assayed by the erythrocytic stages of chloroquine-sensitive strain of Plasmodium falciparum (3D7) in culture using the fluorescence-based SYBR Green I assay. The in vivo assay was done by administering mice infected with Plasmodium berghei (NK65) four consecutive daily doses of the extracts through oral route following Peter’s 4-day curative standard test. The percentage suppression of parasitaemia was calculated for each dose level by comparing the parasitaemia in untreated control with those of treated mice. Cytotoxicity was determined against HeLa cells using MTT assay. Histopathology was studied in kidney, liver and spleen of isolated compound-treated Swiss albino mice. The leaf crude ethyl acetate extract of M. koenigii showed good in vitro antiplasmodial activity against P. falciparum. The in vivo test of the leaf crude ethyl acetate extract (600 mg/kg) showed reduced malaria parasitaemia by 86.6 % against P. berghei in mice. Bioassay-guided fractionation of the leaf ethyl acetate extract of M. koenigii led to the isolation of two purified fractions C3B2 (2.84 g) and C3B4 (1.97 g). The purified fractions C3B2 and C3B4 were found to be active with IC50 values of 10.5?±?0.8 and 8.25?±?0.2 μg/mL against P. falciparum, and in vivo activity significantly reduced parasitaemia by 82.6 and 88.2 % at 100 mg/kg/body weight on day 4 against P. berghei, respectively. The isolated fractions C3B2 and C3B4 were monitored by thin-layer chromatography until a single spot was obtained with R f values of 0.36 and 0.52, respectively. The pure compounds obtained in the present investigation were subjected to UV–visible spectroscopy, Fourier transformer infrared spectroscopy, 1D and 2D 1H-Nuclear magnetic resonance (NMR), 13C NMR, DEPT, COSY and Mass spectral analysis. Based on the spectral analysis, it is concluded that the isolated compounds were myristic acid (C3B2) and β-caryophyllene (C3B4). The cytotoxic effect of myristic acid and β-caryophyllene showed the TC50 values of >100 and 80.5 μg/mL, respectively against HeLa cell line. The histopathology study showed that protection against nephrotoxicity of kidney, hepatic damage of liver and splenocytes protection in spleen was achieved with the highest dose tested at 100 mg/kg/body weight. The present study provides evidence of antiplasmodial compounds from M. koenigii and is reported for the first time. 相似文献
748.
Objective: To evaluate the efficacy of therapeutic hypothermia (TH) using gel packs in reducing mortality and morbidity in term neonates with HIE and study the associated problems with TH. Methods: Hypoxic ischaemic encephalopathy babies were randomized into TH and control group. Babies in TH group were cooled for first 72?h of birth using cloth covered cooling gel packs to maintain target rectal temperature of 33-34°C. Infants were followed up to 6 months and were assessed using Baroda Developmental Screening Test. Results: There were no significant differences in baseline parameters. TH group showed significant reduction in the combined rate of death or developmental delay at 6 months of age by 21% (8.1% in the TH group vs. 29% in the control, RR 0.28, 95% CI: 0.11-0.70; p?=?0.003). Conclusions: TH using gel packs reduces the risk of death or developmental delay at 6 months of age in infants with HIE. Trial registration number: CTRI/2011/06/001780. 相似文献
749.
We evaluated the clinical features, morphology, and incidence of 18 cases of breast lymphoma over 10 years at the University of Alabama at Birmingham. Fine needle aspiration was performed in 7 of 18 patients, and tissue biopsy/resection was available for all 18 cases. Patients were 33 to 91 years old (median, 61); 17 were women and 1 was a man. Fine needle aspiration was consistent with the tissue diagnosis in 6 of the 7 cases (86%). One case was diagnosed by fine needle aspiration as atypical cells, favor benign; the biopsy revealed diffuse large B-cell lymphoma. Tissue diagnoses revealed that 11 cases (61%) represented diffuse large B-cell lymphoma and 3 (17%) were follicular lymphomas. The remaining 4 cases (22%) were plasma cell neoplasm, T-cell neoplasm, Burkitt's lymphoma, and precursor B-cell lymphoblastic lymphoma. Flow cytometry and/or gene rearrangement supported the diagnosis of lymphoma in 8 cases. Although rare, lymphoma should be considered in the differential diagnosis of a breast mass. Fine needle aspiration can facilitate appropriate triage of patients for further management. 相似文献
750.